1. Field of the Invention
This invention relates to a flow imaging cytometer. More particularly, the invention relates to a flow-imaging particle analyzing system in which cells fluorescently stained in a manner suitable for the particular cells of interest are introduced to a flow cell to be formed into a planar sheathed flow and irradiated with white light (strobe light) to obtain a white-light image and excited with laser light to obtain a fluorescent image in a highly efficient manner, and in which the two types of images can be captured simultaneously by a single video camera and subject to analysis.
2. Description of the Prior Art
Attempts have been made to irradiate cells, which have been stained and smeared on a glass slide, with light such as visible light or ultraviolet light under a microscope, capture a fluorescent image of cells of interest, analyze the resulting image and obtain physiological information relating to the cells. However, a method of this kind is not suited to the analytical processing of a large number of cells in a short time, and analysis using fluorescent images has only limited application.
In another example of the conventional flow imaging cytometer, the cell information is obtained using a gross value of the fluorescence emitted from the fluorescently stained cell. In other words, the fluorescence emitted from each portion of the cell is integrated over the entirety of the cell, and the cell information is obtained in the form of such an integrated value. Though such a method lends itself to analysis of a large number of cells in a short period of time, it is not possible to acquire detailed information as to which portions of individual cells have been stained and caused to emit fluorescence. Consequently, this method is limited in terms of analytical performance.
On the other hand, a cell classifying apparatus that has been put into practical use employs a technique in which cells stained in a manner suitable for a particular cell of interest are introduced to a flow cell to be formed into a planar sheathed flow and irradiated with strobe light, a still picture is obtained by a video camera and image processing is applied. However, the state of the art is such that the capturing and analysis of fluorescent images of individual cells using this method have still not reached a practical stage because of problems related to fluorescent imaging sensitivity. The present invention makes use of the technology employed in a flow imaging cytometer of the type having a high image capturing efficiency, as previously proposed in the specification of Japanese Patent Application No. 185794/1990.